Single stem hanger for lighting fixtures



Jan. 3, 1961 G. J. PlCHA SINGLE STEM HANGER FOR LIGHTING FIXTURES Filed Oct. 11, 1957 2 Sheets-Sheet J.-

Jan. 3, 1961 G. J. PICHA 2,967,040

SINGLE STEM HANGER FOR LIGHTING FIXTURES Filed Oct. 11, 1957 2 Sheets-Sheet 2 1 2,96?,40 Patented Jan. 3, 1961 ice SINGLE STEM HANGER FOR LIGHTING FIXTURES George J. Picha, Cleveland, Ohio, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 11, 1957, Ser. No. 689,674

14 Claims. (Cl. 248-324) The invention relates generally to hangers for lighting fixtures or luminaires, and more particularly, to single stem hangers for light fixtures.

In hanging light fixtures, some difiiculties are experienced in adapting a hanger, primarily designed for suspending a fixture from a horizontal support, for use in hanging a fixture from a support extending obliquely to the horizontal. In making installations of light fixtures, it is often found that ceilings and supports from which they are to be suspended do not extend in a horizontal plane. In order to meet such probems, a hanger which will lend itself to use on horizontal ceilings or supports and also on surfaces extending at an oblique angle to the horizontal is required.

The object of the invention is to provide a hanger for light fixtures, the parts of which have a substantially uni versal movement relative to one another to facilitate installation under widefy varying conditions.

Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.

The invention accordingly comprises the features of construction, combination of elements, and arrangement of parts, which will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

Figure l is a view in perspective of a portion of the hanger showing details of the structure;

Fig. 2 is a top plan view of a part of the hanger showing certain of the members in assembled relationship;

Fig. 3 is a view in perspective of the upper portion of the hanger, with an extension which may be employed to cover a surface mounted outlet box;

Fig. 4 is a view in perspective of the upper portion of the hanger with the extension added showing how the elementsof the structure may be set in different positions relative to one another to accommodate it within limits to a support that does not extend in a horizontal plane;

Fig. 5 is a view in side elevation of a hanger with portions cut away to show details of the structure and how the members may be set in different positions relative to one another;

Fig. 6 is a view in elevation of a hanger turned through an angle of 90 from the view shown in Fig. 5 with portions cut away to show how the members may be moved relative to one another to assume different hanging positions on sloped ceilings; and

Fig. 7 is a view in perspective to show how the hanger may be mounted to support a fixture below a false ceiling.

In mounting or suspending light fixtures, the hangers employed have to be attached to many different kinds of supports. In office buildings, some factories, and homes, it is general practice to suspend the hanger from an outlet box. However, there are many situations where the hanger has to be suspended from supports such as the beams supporting a ceiling, two-by-fours, and a variety of other structural members. It is often necessary to suspend the lighting fixture from sloped ceilings extending at an angle to the horizontal or below false ceilings extending in a horizontal plane and sometimes in a plane oblique to the horizontal.

Referring now to the drawings, and Figs. 1 and 2 in particular, the present hanger comprises a bridge shown generally at 10. The bridge 10, is the member that is suspended from any suitable type of support such as the outlet box 11 shown in Figs. 5 and 6.

The bridge 11! comprises a substantially flat plate 12 provided with a plurality of spaced slots. In this particular embodiment of the invention, the plate 12 is provided with two aligned slots 13 at opposite sides, and four others at the corners extending in ditferent directions substantially radially of the center of the plate 12. While in this embodiment, the slots 13 are shown as located along lines extending through the center of the plate 12 it will be appreciated that they can be located in any position in the plate to accommodate it for mounting on any support. With six slots 13 as shown in Fig. 2, the plate may be attached to a great variety of outlet boxes by means of screws 14 shown in Figs. 5 and 6, or to any other type of support ordinarily employed in buildmgs.

As illustrated, the slots are made relatively long with respect to the diameter of a screw. Thus, in mounting the bridge 10 on a support, it may first be loosely mounted by means of a single screw 14 and then adjusted within such limits as the length of the slots 13 or rotated around the screw 14, which has been employed for initially mounting it, to set the bridge in any predetermined position that will best accommodate it for supporting the hanger. After it has been properly adjusted, the screw 14 may be tightened and other screws employed to support the bridge firmly in the required position.

The bridge is provided with two depending integral wings 15 and 16 which, in this embodiment of the invention, extend at substantially right angles to the plate 12. These depending wings 15 and 16 may be made of any shape. Wings, of the shape illustrated, have been found suitable for conditions that it has been found necessary to meet in most structures. The depending wings 15 and 16 have slots 17 and 18, therein respectively. These slots 17 and 18 are shown extending substantiaLy parallel to the plate 12, and are disposed in substantially the same relative positions in each of the wings. The purposes of the slots are to support a member 19 generally known as a swivel bracket which generally will permit one half inch lateral and one half inch longitudinal adjustment. The swivel bracket will be described in detail hereinafter. The hanger bridge 10 may be designed to support a wide variety of fixtures. It may also be employed on supports disposed at different angles.

It will be readily appreciated that the fixture may be made from a great variety of materials and by different shop methods. It has been found in practice that a very satisfactory hanger may be made from stampings that are formed to provide the depending wing members 15 and 16. The bridge illustrated in Figs. 1 and 2 is preferably made from sheet metal by a stamping and forming operation. With a properly designed punch, a blank can be stamped from sheet steel which will include a base 12 and the wings 15 and 16 extending in the same plane as the base. After the blank has been stamped, the wings 15 and 16 may be folded downwardly into a position where they are substantially at right angles to the base 12. In the stamping operation the slots 13, 17 and 18 will be punched in the blank. It is also desirable to punch an opening 20 in the center of the base 12 to take a three-eighths inch nipple or stud 3 that receives the conductors (not shown) that are provided for supplying the current to the light bulbs that will be mounted in the fixtures.

The member or plate 19, shown in Fig. l and re ferred to as a swivel bracket may also be made from sheet steel. It comprises a substantially rectangular plate which is longer than the spacing or distance between the Wings 15 and 16 on the bridge 10. Its Width will be substantially less than the length of the slots 17 and 18. Integral depending members or'lugs 21 and 22 are provided on opposite ends of the swivel bracket 19. In this particular embodiment of the invention, the lugs 21 and 22 extend downwardly from the plate. An opening 23 is provided in the center of the plate. This opening will be slightly larger than the depending stem 24, which will be described in greater detail as the specification proceeds. Lugs 25 and 26 are provided on the sides of the plate 19. These lugs 25 and 26 are utilized to hold the swivel bracket attached to the collar on the stem.

The stem 24 is usually made from an iron tube which is large enough to receive conductors provided for supplying the lamp bulbs carried by the hanger. Near the upper end of the stem 24, a collar 27 is provided. This collar Will be slightly smaller in diameter than the width of plate 1.9. The collar 27 may be attached to the stem 24 in any suitable manner as by welding, swaging or brazing. After the stem 24 has been mounted in the plate 19, the lugs 25 and 26 will be folded upwardly and back on the collar 27. When the lugs 25 and 26 are folded into loose engagement with the collar 27, the stem may be readily turned through 360.

The depending lugs 21 and 22 will be made a little bit shorter in length than the width of the slots 17 and 18 in the wings 15 and 16 in the bridge 10. This will enable them to be readily fitted through the slots for suspending the stem from the bridge 10.

The distance between the metal of the Wing 15 defining one end of the slot 17 to the metal of wing 16 defining an end of slot 18 disposed diagonally opposite is greater than the length of a diagonal of the plate 19. Therefore, when the plate 19 is raised locating the lugs 21 and 2-2 opposite the slots 17 and 13 the plate may be rotated through a predetermined angle around the axis of the stem 24 to engage the plate 19 and lugs 21 and 22 with or disengage them from the Wings 15 and 16. As pointed out hereinbefore, the lugs 21 and 22 are shorter than the depth of slots 17 and 18 and therefore, on rotation of stem 24 the plate 19 and lugs 21 and 22 will pass through the slots.

It is also pointed out that the distance from the outer face of either of the lugs 21 and 22 to the side of the stern remote from either of the lugs 21 or 22 is less than the spacing between the wings 15 and 16. Therefore, in connecting the stem 24 to or disconnecting it from the wings 15 and 16 it can be tilted to fit one of the lugs 21 or 22 through one of the slots 17 or 18 and then the plate 19 is moved through the selected slot until the stem engages a Wing when the stem is swung into a vertical position with the upper end still in contact with the wing. Since the distance from the outer face of either lug to the side of the stem remote from that lug is shorter than the spacing between wings 15 and 16 the plate 19 may then be moved into a horizontal position and then endwise moving the free lug through the free slot in the wings. In this manner the plate 19 and lugs 21 and 22 can be engaged with or disengaged from the wings 15 and 16.

Since the plate 19 is substantially longer than the distance between the wings 15 and 16, when the stem 24 is suspended from the bridge, it may be moved longitudinaliy along the long axis of the plate a predetermined distance. Further, the width of the plate is much less than the length of the slot 17 and 18 and therefore, swivel bracket 19 may be moved back and forth in the slots 17 and 18. The thickness of the sheet metal from which the swivel bracket 19 is made is very much less than the width of the s1ots-17 and 18, therefore, the swivel bracket 19 may be rocked in the slots. It has been found good practice for general use to provide for a swinging of the stem through an angle of about 30 from the vertical. When the hanger is so constructed it can be accommodated to most sloped ceiling installations.

The depending lugs 21 and 22 serve as a stop to prevent the plate 19 from sliding out of the slots 17 and 18 when it is moved along the long axis of the plate 19. The lugs 21 and 22 are described as being turned downwardly at substantially right angles to the plate. It will be readily appreciated that this is only by way of illustration and that lugs that are not set at right angles may be uilized.

The thickness of the sheet metal from which the bridge 10 and swivel bracket 19 are stamped will depend on the strength required. This is well-known by those skilled in the art and can readily be selected when making the design. The brackets heretofore manufactured and which have been found successful are made from sheet steel about in thickness.

Referring now to Figs. 5 and 6, when the hanger is suspended from outlet boxes such as 11 shown in these two figures, it may be swung to either side as shown to meet installation conditions. When the wings 15 and 16 are located as shown in Fig. 6, then the angle through which the stern may be swung from side to side, will depend on the width of the slots 17 and 18 and the width of the swivel bracket 19.

In many instances the hanger will be utilized to suspend fixtures below a false ceiling 28 suspended from a main ceiling 29 by means of hangers 30 as shown in Fig. 7. The spacing between the false ceiling and the main ceiling will determine to some extent the length of the stem 24. In such case, a base 10 and bracket 19 could be suspended from an outlet box extending through the main ceiling 29 or from the main ceiling itself. This type of hanger can readily accommodate itself to main ceilings and false ceilings which extend parallel to one another.

It is general practice to provide hangers with canopies 31 which are mounted on the stem 24 and disposed to engage the ceiling. These canopies 31 are usually required to have ornamental value and to match up with other canopies. They also have utilitarian purposes such as the covering up of unsightly openings in the ceiling through which the stern extends.

In this particular embodiment of the invention, the canopy 31 is made circular and may be said to simulate a bowl. When in position, the mouth of the bowl will be in engagement with the ceiling. The canopy is made circular or symmetrical so that it will match up with the other canopies without giving it a particular set. An opening 32 is provided in the bottom of the canopy which is large enough to receive a resilient split collar 33, the function of which will be described in greater detail hereinafter. In addition to the canopy 31, in some instances it maybe desirable to provide an extension 34 as shown in Fig. 3 and Fig. 4. This extension is generally a sleeve which seats on a flange 43 provided about the mouth of the canopy 31. The extension 34 may be ornamental or plain. It, in effect, is an extension of the canopy 31 and used to cover surface mounted outlet boxes.

The split collar 33 which springs in the opening 32 in the canopy will be large enough to slide easily on the stem 24. It will be made from a resilient material such as spring steel. Usually, the metal from which the stampings or split collar are made has a certain amount of resilience. This is made use of in the split collar. As the term split collar imp-lies, the member 33 has a gap in it on one side.

In order to loosely support the split collar 33 in the opening 32 of the canopy, four knobs or projections 36 are formed by pressing the metal outwardly. These knobs or projections are arranged in pairs. The pairs of projections 36 are disposed opposite to one another and spaced apart a distance somewhat greater than the thickness of the canopy wall.

When it is desired to mount the split collar 33 in the opening 32 in the canopy 31, the gap is pressed closed and two of the knobs projected through the opening. For example, if the split collar was being inserted from the bottom of the canopy while the gap is being held closed, the two top knobs would be projected to a point above the bottom of the canopy. The collar is then released and the knobs projected through the opening 32 engage the bottom of the canopy and hold it in position. Since, the knobs are spaced apart a distance substantially greater than the canopy wall, the split collar may be oscillated in every direction relative to the bottom of the canopy. In other words, the canopy and split collar can be said to have a universal movement relative to one another.

In order to support the canopy in any predetermined position on the stem 24, a set screw 37 is provided in the split collar 33. This set screw will be placed as close to the bottom of the split collar as convenient in order to facilitate reaching it for the purpose of either tightening or loosening.

The foregoing description discloses a single stern hanger, the stem 24 of which may be set at different angles to the bridge to accommodate it to the support on which it is mounted. The canopy may be set at different angles to the stem to apply it to the support or ceiling to which it has to be applied. The whole structure is so constructed and arranged that the members can be moved relative to one another to adapt the hanger to any structure in which lighting fixtures have to be mounted. Further the stem 24 may be made any predetermined length to meet conditions.

Since certain changes may be made in the above construction and difierent embodiments of the invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a hanger for suspending luminaires from a sup port, in combination, a bridge comprising a substantially fiat base having slots therein extending in different directions to facilitate attaching the bridge to the support and adjusting it to substantially any predetermined position, and depending wings extending at substantially right angles to the base, each depending wing having a slot therein extending substantially parallel to the base, an elongated swivel bracket suspended from the wings of the bridge, depending members provIded on the ends of the swivel bracket, the depending members on the swivel bracket being shorter than the depth of the slot to provide for the fitting of them through the slots, and a stem suspended from the central portion of the swivel bracket, the stem being rotatably mounted in the swivel bracket.

2. In a hanger for suspending luminaires from a support, in combination, a bridge comprising a fiat base member having slots therein extending in different direc tions to facilitate the mounting of the bridge on the support and adjusting it to different positions and wings depending from opposed ends of the base, each wing having a slot therein, the slots extending substantially parallel to one another, a swivel bracket, the swivel bracket being provided with end members extending at substantially right angles thereto, the end members of the swivel bracket being shorter than the depth of the slots to provide for the fitting of them through the slots, the swivel bracket being substantially longer than the spacing between the depending wings, a stern suspended from substantially the center of the swivel bracket, the stem being so mounted on the bracket that it may be rotated relative thereto, a split collar loosely mounted on the stem, means disposed in the collar for fastening it in different positions on the stem, a canopy having an opening therein for receiving the split collar, and means provided on the split collar for supporting the canopy, the means provided on the split collar for supporting the canopy permitting universal movement of the canopy relative to the split collar so that the canopy can be mounted flush with the support to conceal the bridge and bracket Within said canopy.

3. In a hanger for suspending luminaires from a support, in combination, a stem, means for suspending the stem from the support, a split collar slidably mounted on the stem, means for fastening the split collar in different positions on the stem, a canopy having an opening therein for receiving the split collar, projections provided on the split collar to engage the opening of the canopy forsupporting the canopy, whereby the canopy and split collar have a universal movement relative to one another to facilitate the positioning of the canopy so that the canopy can be mounted flush with the support to conceal the means for suspending the stem from the support.

4. In a hanger for suspending luminaires from a tilted support, in combination, a mounting member comprising a base having slots therein for attaching it to the support and spaced elongate wings carried by the mounting member, each mounting member wing extending downwardly at right angles to said base, a longitudinally extending slot in each wing parallel to the tilted support, an elongated swivel bracket having opposed members extending generally in the direction of said wings at each of its ends, said swivel bracket being longer than the distance between the mounting member wings and extending through said slots to enable its being suspended from the mounting member, a depending stem being carried by the swivel bracket, said swivel bracket being pivotable and linearly movable relative to said wing slots, and a canopy being supported by a universal connection means on the stem to be flush with said support so that said mounting member and said swivel bracket are concealed Within said canopy.

5. in a nanger for suspending lighting fixtures and the like from a support, in combination, a mounting member comprising a base member having openings therein for attaching the mounting member to the support, and spaced elongated wings having substantially aligned longitudinally extending slots therein and being carried by the base member, an elongated swivel bracket having opposed members extending generally in the direction of said wings for engaging the mounting member wings through said wing slots, the swivel bracket being longer than the spacing between the mounting member wings to enable it to extend through said wing slots to be engaged with the mounting member wings and being pivotable relative to said mounting member wings and being linearly molable relative to said mounting member wings in any reference plane which includes the slots, a stern being carried by the swivel bracket, and a canopy being supported by the stem to be flush with said support, said mounting member and said swivel bracket being concealed within said canopy.

6. In a hanger for suspending lighting fixtures and the like from a support, in combination, a mounting member comprising a base member having openings therein for attaching said mounting member to said support, and spaced elongated wings having substantially aligned, longitudinally extending slots therein being carried by the base member, an elongated swivel bracket having opposed members extending generally in the direction of said wings, the swivel members being of such length that they can readily be fitted through the wing slots, the swivel bracket being longer than the spacing between the wings of the mounting member and being pivotable relative to said mounting member wings and, being linearly movable relative to said mounting member wings in any reference plane which includes the slots, a canopy having an opening therein, a split collar engaging said canopy and in sorted in said canopy opening, means for enabling movement at least through a substantial solid angle of the split collar relative to the canopy, a stem extending through the split collar and engaging said swivel bracket, and means for locking the stem in different predetermined positions in the split collar so that the canopy can be mounted flush with the support to conceal the mounting member and the bracket within said canopy.

7. In a hanger for suspending lighting fixtures and the like from a support, in combination, a mounting member comprising a base for attaching said mounting member to the support, elongated wings being carried by the mounting member and having substantially aligned, longitudinally extending slots, a swivel bracket having opposed members extending generally in the direction of said Wings to be readily fitted through the Wing slots, a stem being supported by the swivel bracket in a manner enabling it to be rotatable relative to the swivel bracke a canopy for enclosing said bracket and said mounting member relative to said support, a split collar being engaged in an opening in the canopy, and means for fastening the split collar in difierent predetermined positions relative to the stem, the split collar being movable at least through a substantial solid angle in the opening in the canopy so that the canopy can be mounted flush with the support to conceal the mounting member and bracket within said canopy.

8. In a hanger for suspending lighting fixtures and the like from a support, in combination, a mounting member having a plurality of slots therein enabling it to be attached to the support in different positions, elongated wings being carried by the mounting member having substantially aligned, longitudinally extending slots therein, a swivel bracket having opposed members extending generally in the direction of said wings, the bracket members being of such a length that they can be readily fitted through the wing slots, the swivel bracket being longer than the distance between the mounting member wings so that the swivel bracket can be suspended from the mounting member wings with its outer ends located in the slots and being pivotable relative to said mounting member wings and being linearly movable relative to said mounting member wings in any reference plane which includes the slots, a stem being suspended from the swivel bracket, a split collar being slidably mounted on the stern, means for locking the split collar in different positions on the stem, a canopy having an opening therein, and means for supporting the canopy on the split collar, said canopy supporting means providing for movement of the split collar relative to the canopy through a substantial solid angle so that the canopy can be mounted flush with the support to conceal the mounting member and the bracket within the canopy.

9. In a hanger for suspending luminaires and the like from a support, in combination, a mounting member comprising a base portion having slots extending in different directions for attaching the mounting member to the support in different positions, spaced elongated wings being carried by the base portion, each mounting member wing having a generally longitudinally extending slot therein, the mounting member wings extending substantially parallel to each other, an elongated swivel bracket for mounting in the wing slots, said swivel bracket being longer than the spacing between the wings to enable it to be supported thereby, opposed members extending generally in the direction of said wings being provided the ends of the swivel bracket, said bracket members being adapted to fit through the slots, a stem being suspended from a central portion of the swivel bracket, the swivel bracket being movable both pivotally and linearly relative to the slots to facilitate positioning the stem in suspending the luminaires in difierent predetermined positions.

10. In a hanger for suspending lighting fixtures and the like from a support, in combination, a mounting member comprising a base portion for mounting the mounting member on the support and for adjusting it to different mounted positions, spaced elongated wings being carried by the base and being positioned substantially parallel to each other, said mounting member wings having substantially aligned, longitudinally extending slots, a bracket having a greater longitudinal dimension than the spacing between the wings to enable it to be supported thereby, opposed members being provided on the ends of the bracket and extending generally in the direction of said wings, the bracket members being shorter than the depth of the Wing slots to enable a fitting of the bracketthrough the wing slots and being spaced from each other and being sized so that when the bracket is positioned in the wing slots it can be retained therein yet linearly moved relative thereto, said bracket also being pivotable relative to said mounting member, a stem being mounted on the bracket and depending therefrom, a slidable member engaging the stem, means for fixing the slidable member in different positions on the stem, a canopy having an opening therein for receiving the slidable member, and means being provided on the slidable member for supporting the canopy, the canopy supporting means providing movement through a substantial solid angle of the slidable member and the stem relative to the canopy, and an extension carried by the canopy so that the canopy can be mounted flush with the support to conceal the mounting member and the bracket.

11. In a hanger for suspending lighting fixtures and the like from a support, in combination, a mounting member comprising a base having openings therein for attaching the mounting member to the support and spaced elongated wings being carried thereby, the mounting member wings having generally longitudinally extending slots therein, an elongated swivel bracket having opposed lugs at its ends extending generally in the direction of said wings, the length of the bracket lugs being shorter than the depth of the slots in the wings, said swivel bracket being locatable at a first position so that, when the lugs are disposed to be opposite the slots and the swivel bracket is rotated to a second position through a predetermined angle in a plane substantially normal to its surface and lowered, the lugs first move through the slots in the direction of their elongation and thenseat outwardly of the wings to enable the swivel bracket to be suspended from the mounting member, and a depending stern being carried by the swivel bracket.

12. In a hanger for suspending luminaries and the like from a support, in combination, a mounting member comprising a base having slots therein for attaching the mounting member to the support and for adjusting it to substantially any predetermined position, and spaced elongated Wings being carried by the base with each mounting member wing having a longitudinally extending slot therein, an elongated swivel bracket being suspended from the mounting member wings, opposed members extending generally in the direction of said wings being provided on the ends of the swivel bracket, the bracket members being shorter than the depth of the wing slots to provide for the fitting of them through the wing slots, and a stem being suspended from the central portion of the swivel bracket, the distance from the outer face of at least one of the bracket members to the side of the stem remote from the one bracket member being shorter than the distance between the mounting member wings to enable the associated one of the bracket members to be fitted through the slot of one mounting member wing and then to enable the swivel bracket to be moved endwise through the one wing slot thereby moving the other end of the swivel bracket and the other bracket member into alignment with the other wing slot so that the swivel bracket can then be moved endwise to fit the other bracket member through the other wing slot and thereby be suspended from the mounting member.

13. In a hanger for suspending lightingfiixtures and the like from a support, in combination, a mounting member comprising a base having openings therein for attaching the mounting member to the support in different predetermined positions, spaced elongated Wings being carried by the base, the mounting member wings each having a longitudinally extending slot therein, an elongated swivel bracket for engaging the slots in the mounting member depending Wings, the bracket being longer than the spacing between the mounting member wings, the width of the bracket being less than the distance between the mounting member wings, opposed lugs being provided at each end of the bracket portion and extending generally in the direction of said wings, the length of the bracket lugs being shorter than the height of the wing slots, and a depending stern being carried by the bracket for supporting a lighting fixture, said swivel bracket being positionable in a first position between the wing slots with its longitudinal axis being generally parallel with the wings and being rotatable about the axis of the stem to a second position wherein the bracket lugs pass through the wing slots to enable the swivel bracket to be suspended from the wings when lowered to seat thereon.

14. Apparatus for suspending lighting fixtures and the like from a support, said apparatus comprising a mounting member for securing the apparatus to said support, said mounting member including spaced elongated portions extending outwardly from said support and having substantially aligned, longitudinally extending slots therein, and means engageable through said slots with said spaced portions for supporting said light fixture from said mounting member, said supporting means being linearly movable relative to said mounting member in any reference plane which includes said slots and being pivotable relative to said mounting member, and means for enclosing said supporting means and said mounting member relative to said support.

References Cited in the file of this patent UNITED STATES PATENTS 947,550 Ramsey Jan. 25, 1910 1,895,050 Russell Jan. 24, 1933 2,102,462 Howell Dec. 14, 1937 2,516,661 Versen July 25, 1950 2,739,780 Richards Mar. 27, 1956 2,815,918 Wolar Dec. 10, 1957 FOREIGN PATENTS 579,671 Germany July 1, 1933 

